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Highlights: [•] The photolysis of low concentration of H2S malodorous gas. [•] Self-made high frequency discharge electrodeless lamp. [•] Effects of relative humidity and gas environments. [•] Mechanisms for direct and indirect photolysis (ozone and radical generation). [Copyright &y& Elsevier]

This study examined the UV/H2O2 decolorization efficiency under high UV photon flux (intensity normalized by photon energy) irradiation; the incident UV was ranging from 3.13 × 10−8 to 3.13 × 10−6 einstein cm−2 s−1. The experimental results showed that complete decolorization of 20 mg L−1 methylene blue (MB) can be achieved within 5 s and 99% decolorization of 1000 mg L−1 MB can be achieved in 180 s under the best condition of high UV intensity UV/H2O2 process. To the best of our knowledge, UV/H2O2 decolorization process in such a short time has not been reported. The electrical energy per order of the process was 16.21 kWh m−3 order−1 and it is relatively economical compared with other advanced oxidation processes. The kinetics of decolorization follows pseudo-first order. There is a linear relationship between rate constant and UV intensity, which indicates that increasing UV intensity does not cause decline in light utilization efficiency. The experiment related to initial substrate concentration shows decolorization rate of different substrate concentration (20-1000 mg L−1) are closed to each other. Besides, optimal H2O2 concentration, comparative study with low photon flux light, decolorization of other types of dyes and TOC removal were also studied. [ABSTRACT FROM AUTHOR]

Abstract: UV/TiO2/H2O2 decolorization of methylene blue (MB) was studied under high UV photon flux irradiation; the UV photon flux in this work was ranging from 3.13×10−8 to 3.13×10−6 einsteincm−2 s−1. It was shown that photodegradation using UV/TiO2/H2O2 process was much more effective than UV/TiO2 process. Under the optimal conditions of UV/TiO2/H2O2 process, 98% decolorization of 20mgL−1 MB could be achieved in 10 s. Kinetics of UV/TiO2/H2O2 decolorization follows pseudo-first order with respect to the dye concentration. In UV/TiO2 process, the photocatalytic rate constant increased with the square root of photon flux under high photon flux UV irradiation, and addition of H2O2 could turned the square root relationship closed to linear relationship. The apparent photonic efficiency under various experimental conditions have been calculated and the results also clarified that H2O2 could improve the light utilization efficiency of photocatalytic process. The electrical energy per order (EEO ) values showed that adding H2O2 could reduce energy consumption remarkably. Besides, effect of H2O2 concentration, effect of MB initial concentration and TOC removal were also studied. [Copyright &y& Elsevier]

Abstract: Heterogeneous photo-Fenton process using LiFe(WO4)2 as catalyst was studied to degrade Methylene blue (MB) dye in aqueous solution. The results indicated that LiFe(WO4)2 could effectively catalyze the decolorization of MB in the presence of UV light and H2O2. The effects of different parameters such as amounts of catalyst, H2O2 concentration, initial pH of the dye solution, initial dye concentration and UV light intensity on the decolorization efficiency of the process were investigated. It was found that LiFe(WO4)2 possessed a wide applicable pH range. X-ray photoelectron spectroscopy (XPS) was applied to investigate the transformation between Fe(III) and Fe(II). It was also observed that catalytic behavior could be reproduced in consecutive experiments without a considerable drop in the process efficiency. [Copyright &y& Elsevier]

Abstract: A novel thin-film apparatus with quartz optical fibers for UV-light delivery was tested for its potential to inactivate bacteria in beer. Its suitability for application could be shown in experiments with Escherichia coli, Lactobacillus brevis, Saccharomyces cerevisiae and naturally contaminating microorganisms as test microorganisms. We have optimized the optical-fiber distribution density (ODD) and thin-film thickness for treating beer. The apparatus could reduce counts of inoculated E. coli and L. brevis in beer from approximately 106 CFU/ml to below 1×101 CFU/ml and from approximately 104 CFU/ml to non-detectable limits at UV doses of 16.1 and 9.7mJ/cm2 by the thin-film apparatus respectively. The reduction of S. cerevisiae was not so efficient. Naturally contaminating lactic acid bacteria and Enterobacteriaceae in draft beer could be effectively inactivated. Furthermore, the beneficial yeasts in the draft beer were scarcely inactivated. These results implicate that application of this novel apparatus provides a promising approach to improving microbial safety and extending shelf-life of draft beer. [Copyright &y& Elsevier]